Electric switch, circuit-breaker, and the like.



D. K. MORRIS & G. A. LISTER. ELECTRIC SWITCH, CIRCUIT BREAKER, AND THE LIKE.

APPLICATION FILED MAR. 23,1912.

Patented Aug. 26, 1913.

8 SHEETS-SHBET 1.

Fig.1

we a M m M M /S R %n m d r A w a w 8 E w is D. K. MORRIS & G. A. LISTER.

ELECTRIC SWITCH, CIRCUIT BREAKER, AND THE LIKE. APPLICATION FILED MAILZS, 1912.

1,071,566, I Patented Aug. 26, 1913.

3 BHEETS-SHEET 2.

D. K. MORRIS & G. A. LISTER. ELECTRIC SWITCH, 011mm BREAKER, AND THE LIKE.

APPLICATION FILED MAR.23, 1912. 1 071 566. Patented Aug. 26, 1913.

3 SHBETS-SHEET 3.

w/rlyzsssas UNITED STATES PATENT orrrcn DAVID KING MORRIS AND GEORGE ANSLOW LISTER, OF COVENTRY, ENGLAND,

SIGNORS TO MORRIS & LISTER LIMITED, F COVENTRY, ENGLAND.

Specification of Letters Patent.

Patented Aug. 26, 1913.

Application filed March 23, 1912. Serial No. 685,713.

To all whom it may concern:

Be it known that we, DAVID KING MORRIS,

' Ph. 1)., and Gnoncn ANsLow LISTER, B. Sc.,

subjects of the King of Great Britain, residing at Carlton Works, Lockhurst Lane, Coventry, in the county of Warwick, England, engineers, have invented certain new and useful Improvements Relating to Electric Switches, Circuit-Breakers, and the Like, of which the following is a specification.

This invention relates to switches or circult breakers of the thermal type, and has for its object toprovide improved means for liberating the switch .or the like.

The invention comprises the combination with a tension member adapted to be heated by a current passing through or around it and means for retaining the switch or the like in the closed position, of a spring or equivalently controlled oscillatory strut like member on which the tension member is adapted to exert or modify an approximately endon pressure and which can move through a certain angular distance on either side of a dead center (where the force exerted by the tension member is directly along the principal axis of the strut like member) the arrangementof the parts being such that the strut like member normally secures the switch in the operative po sition, but when the tension member is sutlicicntly heated or cooled the strut like member can swing into a position on' the opposite side of its dead center and thereby re lease the switch.

The invention also comprises the arrangement with the strut like member and switch retaining meansof a handle as hereinafter described.

Referring to the three accompanying sheets of explanatory drawings: Figures 1 and 2 are respectively side and rear elevations of a switch having this invention applied thereto. Figs. 3 and 4 are sectional side elevation and sectional plan showing a portion of a modified form of such switch. Figs. 5 and 6 illustrate by side elevation and rear elevation respectively two further modified forms.

The same reference letters in the different views indicate the same or similar parts.

In carrying this invention into effect as shown in Figs. 1 and 2, a pair of tension st rips a connecting together the movable contacts I) on the switch arm 0 which is made of insulating material are deflected in an outward direction at their central portion, and between such portions a forked "catch or retaininglever 05 (or lever formed from a pair of side members) is pivoted on the front end of the switch arm 0. The said lever is adapted to cooperate with an actuating lever e connected to a handle f," which latter (21c. e and f) are secured in the closed position for example, by a spring catch f, acting on the spindle f of the handle f and lever e. Between each side of the catch lever d and the adjacent tension strip is mounted a strut piece g which is hinged or adapted to abut in recesses in the sides of the said parts and is capable of swinging through a certain distance on either side of a line perpendicular to a chord joining the ends of the tension strip.

Assuming the catch lever aforementioned and the actuating lever to be engaged as shown, the strut on each side of the catch lever is in such an angular position that it retains the cross pin it on'the catch lever in engagement with the actuating lever under the action of the thrust imposed on it by the tension. member. The said engagement is effected by the abutment of the pin it against a the roller 6' on, the lever e. The switch arm can therefore be closed and held in theclosed position by the spring catch f above mentioned In the event of the thermal ele-' ments being sufliciently extended by the current passing through or around them, the pressure on the ends of the struts becomes sufliciently relieved to permit the catch lever to be swung by any convenient spring, which is preferably concealed, and coiled 'around the spindle f in the bases 0 whereby the arm 0 is carried on said spindle, out of en gagement' with the actuating lever, so that the switch arm is thereby released and permitted to be opened by the usual springs, which are preferably concealed,and coiled about the spindle f in the bosses c whereby the arm 0 is carried on said spindle. During such movement of the. catch lever eachstrut is swung to the opposite side of its'dead center as indicated by the dotted lines in Fig. 2, and in consequence the catch lever cannot automatically resume its 0perative position, but requires to be moved thereto by the attendant. For conveniently effecting restoration of the catch lever a pro jection a on the actuating lever may be arranged toimpart the desired motion to the catch lever through an abutment plate j when a movement into the open position is given to the actuating lever. In Fig. 2 the arm 0 is broken 'away around. the lever d to show the latter and the plate j more clearly. By employing a separate pair of contacts with each of a pair of thermal elements, and insulating the said contacts from each other, a simple form of double pole switch can be produced as illustrated at Figs/1 and 2.

In carrying out the invention a large variety of different arrangements of the tension and strut members and switch retaining means may be utilized. Further the invention is not limited to loose handle circuit breaking devices as it is equally applicable to other forms of such apparatus.

Referring to the modified forms shown in the drawings, the arrangement illustrated in Figs. 3 and 4 is similar to that in Figs. 1 and 2 excepting that pro-vision is made for preventing violent impact of the actuating lever against theicatch lever when the actuating lever is suddenly operated. Between the two levers is interposed a connecting lever is which is pivoted at If to the switch arin and is attached to the abutment plate 7' by a spring Z. .The switch arm is held in the closed position'by the engagement of the lever e with a pin m on the lever is. When, however, the catch lever is moved to the opposite side ofits dead center as above described, the lever k is withdrawn by the spring] from the lever e and the switch arm 7 is at liberty to be swung into the open position. Restoration of the levers d, e. and 7c is effected bypressure of the lever e on the plate 7' through the pin 71, the-said lever 6 being at the same time caused 'to swing the lever k back against the action of its spring by abutment against a pin n.

In the arrangement diagramatically shown in Fig. 5, a pair of contacts are connected by asingle strip (land on the switch arm is pivoted a handle f connected to a lever e which at one end can engage a projection 0 and at the other end is held by contact with the strip. When the strip expands I the pressure which normally holds the. catch 1n its operative position is released and the catch is withdrawn from thelprojection 0 by the sprmg p. The switclr arm can, then .open. Before reclosing the switch the catch 1s returned to itsoperativeposition by the handle through-the medium of a peg 8 which can be pressed by the handleagainst cally the up er side of the lever e.

t e, arrangement shown diagrammatim'ounted 0 same shaft f we claim as new and desire to in Fig. 6, a pair/of contactsb are the opposlte ends of a levere" 65. W'hlCh 1s looselypivoted at-its: center on the by dotted lines. On one of the contacts (e. g. the upper one) is pivoted a rocking element 6, to a pin F2 on which is connected the extensible strip a whose other end is secured to the other contact 6. The rocking element canmove on the ivot q, and can be engaged by the lever-e t rough the pin h. The lever 03 is operated by a handle f fixed to the same shaft f as the lever e. In the position of the parts shown in the figure, the switch is closed. When the strip expands the element 6 can be rocked by a spring (preferably coiled around the pivot) so that the strip occupies the position shown by the dotted line, and in moving into this position the pin it is withdrawn from the lever 6 so that the switch arm is left free to be swung into the open position by a spring coiled around the shaft f Restoration of the lever e to its operative position is efiected by moving it backward until it takes up the required osition behind the pin 71,, the part I) being restored to the original position by any convenient means, such as a peg 6 against which the rear side of the. lever 6 can be made to abut under the action of the handle ff The ball and spring device 1- is one form of catch which may beconvenientlyused for actin on the levere to retain the switch arm in t e closed position. In this construction the portion of the movable part b which lies between the point of attachment of the strip and the pivot q corresponds to the strut which, as herein stated, is .always. required in conjunction with the tension member. I

The fixed contacts in the switches shown are denoted by s. It will be' understood that in the construction of the switches any suitable installation of the parts adopted. All the springs required and menmay be tioned are not illustrated as these may be of various forms and arrangements.

' Having thus described our invention what secure by Letters Patent is 1. Ina device ofthe class described, the combination with a tension member adapted to be heated and extended by a current and means for retaining the switch in the closed position, of-an oscillatory strut like member on which the; said tension member is adapted to exert-or mQ ifyan approximately end 0D. pressure and wh ch can move through a certain angular distance on either side of a dead -center, the said strut member being adapted normally to secure the switch in the operative position but to swing into a position' onthe opposite side,of its dead center and thereby release the switch when the tension member is sufficiently varied, substantially as described) 2. In adevice of the class described, the I .combination comprising a tension member as the lever c, and 1s indicated adapted to be heated and extended by acurrent, an oscillatory strut like member adapted to occupy a position on either side of a dead center and to keep the switchclosed under the action of the said tension member when in one of said positions,

switch when the temperature of the tension member is sufliciently varied, substantially as described.

3. In a device of the character described, the combination comprising a pair of tension elements, a switch retaining lever, and toggle like pieces interposed between said elements and lever, substantially as described.

4. In a device of the character described, the combination comprising a pair of tension elements, a switch retaining lever, toggle like pieces interposed-between said elements and lever, and an operating lever adapted to be engaged by said retaining lever, substantially as described.

5. In a device of the character described, the combination comprising a pair of tension elements, a'switch retaining lever, tog

gle like piecesinterposed between said elements and lever, an operating lever'adaptod to be engaged by said retaining lever, and a projection on the operating lever and an abutment on the retaining lever for restoring the retaining lever to its operative position by actuation of the operating lever, substantially as described.

and a spring whereby the strut member is moved into the other of the said positions for releasing the -6.. In a device ofthe character described,

the.combination comprising a PBAE'OZE ten sion elements, a switch retaining lever, tog gle like pieces interposed between said el'ements and lever, an operating lever adapted to be engaged by said retaining lever, a connecting lever taining levers, and a spring between said connecting and retaining levers, substan-v tially as described. v

7. In a device. of the character described, the combination with a switch arm, a pair of contacts thereon and apair of tension elebetween the operating and re-' p ments connecting said contacts, of an operatiiig lever pivoted co-axially with the arm and capable of moving independently thereof, a retaining lever pivoted on said arm,

toggle like pieces between said tension elements and the retaining lever, a spring for rocking the retaining lever when released by the tension elements, and a projection on the operating lever andan abutinent on the retainingelever for restoring theretaining lever to its operative positionby actualever, substantially as 

